Airfoil members such as wings, horizontal and vertical stabilizers, canards, rotor blades, winglets, etc. are limited in ability to change their sizes and shapes so as to alter surfaces of the airfoil member and be adaptable to multiple flight conditions of a flight envelope.
Currently, airfoil member surfaces of an aircraft can be modified to a certain extent by various devices for improved flight characteristics such as during low-speed takeoff and descent, autopilot maneuvering, or for high-speed aerodynamics. Aircraft that need to operate in several performance environments, however, often must compromise flight performance by using airfoil members that do not provide suitable characteristics in multiple environments rather than using airfoil members that are specifically designed for a particular flight situation.
Aircraft designs known today utilize a variety of airfoil member surface modifying devices such as, flaps, slats, flaperons, ailerons, split ailerons, or other leading or trailing edge devices known in the art, to provide control forces and moments during flight. Also, other devices such as micro flow devices, zero mass jets, and the like are used to control the airflow over the airfoil member to further control forces and moments. Additionally, devices such as smart materials are used to slightly modify the shape of the airfoil member itself or of the airfoil member surface modifying devices. However, all of these devices are limited in their ability to alter shape, size, and characteristics of the airfoil member; the airfoil member devices typically only modify a single aspect of the airfoil member, minimally affect airflow, or slightly modify shape of the airfoil member. Furthermore, all of the above-stated devices tend to use motors or actuators and other mechanical components to perform minor changes in an airfoil surface.
Military aircraft have utilized mechanically swept wings for improved aerodynamics during high-speed flight. These mechanical surface systems, however, typically only provide a very limited ability to affect airfoil member shape and aerodynamic flight characteristics of the aircraft. The limited ability to significantly change airfoil member shape can result in an airfoil member that is particularly suitable for only a limited range of a flight envelope.
It is therefore desirable to provide an airfoil member and an airfoil member altering system that significantly modifies shape and size of the airfoil member and at the same time provides an airfoil member with increased adaptability for various flight conditions throughout a flight envelope. An airfoil member with improved adaptability may potentially be capable of supporting greater payloads at lower speeds and during take-off and landing of an aircraft, better aerodynamic characteristics at high speed, and increased flight range.
The copending application Ser. No. 10/357,022 as referenced above, as well as U.S. Pat. No. 6,786,457, teaches geometric morphing of an airfoil by changing the inflated state of the inflatable members in the airfoil.